Photo Credit: Wikipedia / Solar Energy - A solar energy powered airplane
The purpose of this article is to provide clarifications on some of the technical details and terms used in a very popular article regarding the setting of solar-power generation record by Germany earlier this year. My comments are written in red and the relevant original texts are highlighted in yellow.
Germany sets new solar power record, institute says
By Erik Kirschbaum
BERLIN | Sat May 26, 2012 7:02pm BST
(Reuters) - German solar power plants produced a world record 22 gigawatts of electricity per hour - equal to 20 nuclear power stations at full capacity - through the midday hours on Friday and Saturday, the head of a renewable energy think tank said.
My comments: 22 gigawatts of electricity per hour doesn't sound right. I learn in physics, 1 watt of power = 1 joule of energy per second. So, 22 gigawatts of electricity per hour = 22,000,000,000/60 joules of energy per second per seconds. Dimensional analysis tells us there is no such thing as "joules per second per second" !!!!
In my opinion, the world record should be interpreted as:
22 gigawatt-hours of electrical power was produced on an hourly basis, measured through the midday hours on Friday and Saturday when the sun was shinning strong with little or no clouds above.
The German government decided to abandon nuclear power after the Fukushima nuclear disaster last year, closing eight plants immediately and shutting down the remaining nine by 2022.
Norbert Allnoch, director of the Institute of the Renewable Energy Industry (IWR) in Muenster, said the 22 gigawatts of solar power per hour fed into the national grid on Saturday met nearly 50 percent of the nation's midday electricity needs.
Comments: Again, it should be interpreted as 22 gigawatt-hours of energy produced on an hourly basis, measure over the said Friday/Saturday sunny period.
"Never before anywhere has a country produced as much photovoltaic electricity," Allnoch told Reuters. "Germany came close to the 20 gigawatt (GW) mark a few times in recent weeks. But this was the first time we made it over."
Comments: The 22 gigawatts is the power output during a day-and-a-half of sunny weather, not 24/7 over any length of time.
The record-breaking amount of solar power shows one of the world's leading industrial nations was able to meet a third of its electricity needs on a work day, Friday, and nearly half on Saturday when factories and offices were closed.
Comments: Let's hope for more sun over the solar plants in Germany !!!
Government-mandated support for renewables has helped Germany became a world leader in renewable energy and the country gets about 20 percent of its overall annual electricity from those sources.
Germany has nearly as much installed solar power generation capacity as the rest of the world combined and gets about four percent of its overall annual electricity needs from the sun alone. It aims to cut its greenhouse gas emissions by 40 percent from 1990 levels by 2020.
Comments: Given that Germany does not have major sources to generate hydro-electricity, the exploitation of solar energy is a smart move.
Some critics say renewable energy is not reliable enough nor is there enough capacity to power major industrial nations. But Chancellor Angela Merkel has said Germany is eager to demonstrate that is indeed possible.
The jump above the 20 GW level was due to increased capacity this year and bright sunshine nationwide.
The 22 GW per hour figure is up from about 14 GW per hour a year ago. Germany added 7.5 GW of installed power generation capacity in 2012 and 1.8 GW more in the first quarter for a total of 26 GW capacity.
"This shows Germany is capable of meeting a large share of its electricity needs with solar power," Allnoch said. "It also shows Germany can do with fewer coal-burning power plants, gas-burning plants and nuclear plants."
Allnoch said the data is based on information from the European Energy Exchange (EEX), a bourse based in Leipzig.
The incentives through the state-mandated "feed-in-tariff" (FIT) are not without controversy, however. The FIT is the lifeblood for the industry until photovoltaic prices fall further to levels similar for conventional power production.
Utilities and consumer groups have complained the FIT for solar power adds about 2 cents per kilowatt/hour on top of electricity prices in Germany that are already among the highest in the world with consumers paying about 23 cents per kw/h.
German consumers pay about 4 billion euros ($5 billion) per year on top of their electricity bills for solar power, according to a 2012 report by the Environment Ministry.
Critics also complain growing levels of solar power make the national grid more less stable due to fluctuations in output.
Merkel's centre-right government has tried to accelerate cuts in the FIT, which has fallen by between 15 and 30 percent per year, to nearly 40 percent this year to levels below 20 cents per kw/h. But the upper house of parliament, the Bundesrat, has blocked it.
($1 = 0.7992 euros)
Comments: All kilowatt/hour and kw/h should be kilowatt-hour and kw-h !!!!
BTW, here are the average monthly electricity bill paid by households across Canada http://www.ontario-hydro.com/index.php?page=current_rates